The purpose is to conduct a pilot study in Colorado to investigate methods for determining the prevalence of traumatic brain injury (TBI) in the nursing home population, where little is known about the prevalence of traumatic brain injury and the characteristics of the nursing home residents with TBI. The specific aims are: 1) to validate the diagnosis of TBI on the Resident Assessment Instrument's Minimum Data Set (MDS) Tool, a federally-mandated data system used by all nursing homes in the United States; 2) to identify cases of TBI missed by the MDS; 3) to use the MDS, if valid, to determine the prevalence of TBI in nursing home residents in Colorado; and 4) to describe the functional status as measured by the activities of daily living and demographic characteristics of nursing home residents with TBI in Colorado. Methods: Investigators will seek approval from the Centers for Medicare and Medicaid Services (CMS) to use part of the MDS data for this project, by completing the CMS process to obtain a data use agreement. For a random sample of nursing home residents with an ICD-9-CM code for TBI or a diagnosis of TBI on the MDS, investigators will verify the TBI using three sources of medical information: the medical records at the nursing homes, inpatient medical records, and the Colorado TBI surveillance system. If a medical diagnosis of TBI or the clinical criteria for TBI as defined by the Centers for Disease Control and Prevention is documented in any of the three sources, then the TBIon the MDS is accurate. To quantify the accuracy of TBI on the MDS for the sample of residents, the investigators will calculate the positive predictive value. Under the provisions of a data use agreement with CMS, investigators will analyze the demographic characteristics and activities of daily living for residents with TBI.